On the go and no time to finish that story right now? Your News is the place for you to save content to read later from any device. Register with us and content you save will appear here so you can access them to read later.

A former New Zealander now living in Denmark says her son was killed when he travelled to Syria to fight with Islamic State (Isis) after authorities failed to stop him.

Karolina Dam, formerly of Auckland but now living in Denmark, told Radio New Zealand her 18-year-old son Lukas died in an American air strike on a building that he was guarding on the Syria-Turkey border.

She found out about his death from Facebook message posted by message, posted by fellow Islamists celebrating his "martyrdom".

The air strike happened last December, six months after Lukas travelled to the Middle East, his mother told RNZ.